local sharing_custom_keys = {
    'FooterId'
}
local revealjs_custom_keys = {
    'WorkSource',
    'Citations'
}

function Meta(meta)
    local meta_tag_template = '<meta name="%s" content="%s">\n'
    -- add sharing keys
    local tags = ""
    for j = 1, #sharing_custom_keys
    do
        local i = sharing_custom_keys[j]
        if meta[i]
        then
            tags = tags .. string.format(meta_tag_template, i, pandoc.utils.stringify(meta[i]))
        end
    end
    -- add revealjs keys
    if FORMAT == 'revealjs'
    then
        tags = tags .. '<meta name="DocumentType" content="revealjs">\n'
        for j = 1, #revealjs_custom_keys
        do
            local i = revealjs_custom_keys[j]
            if meta[i]
            then
                tags = tags .. string.format(meta_tag_template, i, pandoc.utils.stringify(meta[i]))
            end
        end
    end
    quarto.doc.include_text('in-header', tags)
    -- table.insert(meta['header-includes'], pandoc.RawBlock('html', tags))
    return meta
end